The design of a composite laminate involves specifying one or more fiber angles for each composite ply in the composite laminate. For example, a structural design engineer may specify the fiber angles of each composite ply measured relative to a reference direction on the surface of the composite ply. For visualization and for use in computational algorithms such as stress analysis software programs, the fiber angles may be represented by a vector field on the surface of the composite ply. For manufacturing the composite ply, a manufacturing engineer may model the fiber angles as continuous fiber paths when programming automated layup equipment. For example, an automated fiber placement machine (AFPM) may be programmed to lay up a plurality of variable-width courses comprising multiple composite tows along the fiber paths to form each composite ply. Each course may contain a predetermined quantity of composite tows, each of which is a continuous strip of unidirectional composite material. The AFPM may lay up a plurality of composite plies on top of each other to form a composite layup. The composite layup may be cured or hardened to form the composite laminate.
For a composite ply having a planar shape and a constant fiber angle distribution, the fiber paths are straight and parallel to each other. When a planar composite ply with constant fiber angles is laid up such as by using an AFPM, the courses may be aligned edge-to-edge with no overlaps and no gaps between adjacent courses. However, for a composite ply having a curved contour and/or a non-constant fiber angle distribution the fiber paths that follow the fiber directions specified in the fiber angle distribution may not be parallel to each other. As a result, the courses may converge and/or diverge at certain locations on the composite ply, causing overlaps and/or gaps between adjacent courses. The overlaps and gaps may negatively impact the structural properties (e.g., strength, stiffness), surface quality, and manufacturability of the composite laminate. Furthermore, the inability of design engineers to consider the effects of convergence and divergence on the manufacturability of a composite laminate may lead to expensive and time-consuming rework of the composite laminate during manufacturing. In addition, the inability to consider convergence and divergence during the design stage of a composite laminate may mean that more efficient designs are never considered.
As can be seen, there exists a need in the art for a system and method for determining fiber paths that match the fiber angle distribution specified for a composite ply and which allows for optimizing the spacing of the fiber paths by quantifying the convergence and/or divergence of such fiber paths.